Carbureter



C. C. BRADBUHY.

CAHBURETEH.

APPLICATION FILED .IUNE26, i919- 1,350,001 Patented Aug. 17, 1920.

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APPLICATION FILED JUNE 26, |919. 1,350,001.

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Patented Aug. 17, 1920.

UNITED STATES PATENT OFFICE.

CLIFFORD C, BRADBURY, OF OAK PARK, ILLINOIS, ASSIGNOR TO CURTIS B. CAMP, OAK PARK, ILLINOIS, AND LYNN A. WILLIAMS, OF EVANSTON, ILLINOIS, JOINT TRUSTEES.

CARBURETER.

To aZZ whom t may concern Be it known that I, CLIFFORD C. BRAD- IaUnY, a citizen of the United States, residing at Oak Park, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Carbureters, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings forming a part of this specification.

- My invention relates to carbureters for internal combustion engines, and more especially to that type known as suction feed carbureters, wherein fuel is lifted from a low level supply tank to the carbureter body by the suction produced in the intake manifold of the engine to which the carbureter lsupplies fuel.

Although the arrangement of my invention may be applied to various forms of vacuum feed carbureters, it finds particutain predetermined vacuum or reduction of pressure which is substantially constant. The improved valve mechanism of my invention may be arranged to function in two separate and distinct ways, in one of which it is adapted to regulate the vacuum in the chamber by admitting air to the chamber after a certain predetermined vacuum has been produced therein. In the second arrangement, the improved valve mechanism nection withthe accompanying drawings,

wherein- Figure 1 is a cross sectional view taken through a carbureter provided with the improved arrangement of my invention.

Specification of Letters Patent.

Patented Aug. 1'7, 1920.

Application le .Tune 261919. Serial No. 306,831.

Fig. 2 is a fragmentary vertical cross sectional view of a modified arrangement.

Fig. 3 is a View similar to Fig. 2 of a further modification.

Fig. d is a fragmentary vertical cross sectionalwview of another modification of the invention.

F ig. 5 is a view similar to Fig. 4, showing a further modification wherein the interior of the gage tubing hereinafter referred to is subjected to the reduced pressure created in the float chamber, and the exterior thereof subjected to atmospheric pressure.

'Similar characters of reference refer to similar parts throughout the several views.

Referring first to Fig. 1 G designates the main casting of the carbureter provided .with a passageway, 7, controlled by a throttle, 8, mounted on the shaft, 9, and operated by the lever, 10, in the usual manner. Communicating with the passageway, 7, and attached to the casting, 6, is a horn, 11, provided with a primary air intake passageway` 12. This air intake passageway of the horn communicates with a similar passageway, 13, formed in the main casting, 6. The secondary air intake passageway of the horn is controlled by a butterfiy valve, 14, mounted for rotation on the shaft 15, and connected through a link, 16, with a piston, 17, reciprocably mounted in the cylinder, 18. A. coil compression spring, 19, is interposed between the upper face of the piston, 17, and the casting, 6, the tendency of the spring being to hold the piston and thus the valve, 14, through the link connection 16, in the position shown in the drawing.

Fixed within the passageway, 7, of the main casting, 6, is a large venturi, 20, which has communication with the upper end of the cylinder, 18, through the duct, 21. The duct, 21, may, if desired, be controlled by the manually operable Valve shown at 22.

Extending upwardly into the large ven- -turi, 20, and communicating with the primary air intake passageway, 13, is a venturi shaped fuel nozzle, 23, having a step or suddenly enlarged portion, 24, formed therein slightly posterior to its throat. EX- tending around the nozzle, 23, and formed in the spider, 25, is an annular chamber, 26,

v which has communication with the interior of the nozzle, 23, at the above mentioned step in the nozzle through the several fuel openings, 27-27. The annular chamber, 26, also communicates with the fuel supply duct, 28, in turn communicating with the duct 29, extending vertically in an airtight float chamber, 30. This float chamber is bolted, or otherwise secured to the main casting, 6, and contains the usual float mechanism, 31, adapted to control the fuel intake port, 32. 33 designates a metering pin which extends upwardly through the base of the amount of fuel supplied to the duct, 29, and thus to the fuel nozzle, 23.

Extending through the casing, 6, and affording communication Vbetween the atmosphere and the passageway, 7, at a point posterior to the throttle, 8, is a small venturi, 34, containing several ducts, 35, located slightly posterior to its throat, and communicating with the annular chamber, 36, in turn communicating with the duct, 37, extending longitudinally through the casing, 6. The lower end of the duct, 37, communicates with the duct, 38, which extends through the float chamber casing and communicates with the interior of the float chamber at a point above the normal level of fuel therein.

Mounted in the duct, 38, is a valve, 39, carrying a valve stem, 40, which coperates with the spider, 41, for the purpose of guiding the valve in its movement. A compression spring, 42, is interposed between the spider, 41, and the valve, and tends to hold vacuum or reduction of pressure is produced the valve open so that normally communica t'ion is provided between thesmall venturi, 34, and the interior of the oat chamber.

Extending through the float chamber cover, 43, is a tube, 44, to the inner end of which is attached the spiral shaped gage tubing, 45.

Fig. 2 shows aplan view ofthe spiral shaped gage tubing. The tube, 44, communicates with the interior of the gage tubing at one end thereof, and the other'endI of the tubing is sealed, as is most clearly shown in Figs. 2 and 3. By this arrange ment, the interior of the spiral shaped gage tubing is subiected to atmospheric pressure, while the exterior thereof is subJected to whatever pressure is produced in the float chamber. The several parts constituting the valve mechanism, 39 and 45, are adjusted so that normally the valve, 39, is held open by the spring, 42,'the outer end of the valve, 39, resting against the free end of the spiral shaped gage'tubing, 45.

In the operation of the carbureter, a

in the passageway, 7, at a point posteriorto the throttle, 8, with the result that air is taken in through the small venturi, 34. The action of the small Venturi-tube, 34, is such ioat chamber and cont-'rols the,

that a higher degree of 4vacuum or suction is produced in the several ducts, 35, and thus in the annular chamber, 36, than is produced in the passageway, 7. This increased vacuum or suction is communicated to the fioat chamber through the ducts, 37 and 38. When a certain predetermined Vacuum which is suficient for lifting fuel from the main fuel supply reservoir up to the oat chamber has been produced, the spiral shaped member 45 is caused to expand, due to the difference in pressure between the interior and the exterior thereof, with the result that the valve, 39, is moved against its seat and prevents further communication between the venturi, 34, and the float chamber, until the vacuum or suction in the oat chamber has been reduced to that amount which permits contraction of the member, 45, and the opening of the valve member 39. The several parts, 14,16 and 17 function to maintain in the passageway, 7, a suction which is sufficient for producing the required vacuum at the throat of the venturi, 34.

ln Fig. 2 l have shown a slightly modified arrangement, in which the small venturi, 34a, is located at a point anterior to the throttle, 8, and has communication through the duct, 46, with the duct, 38a, in turn communicating with the float chamber above the normal level of fuel therein. In this case, the small venturi, 34, is preferably located at a. point anterior to the large venturi shown at 20 in Fig. 1, and substantially in the same horizontal plane as the duct 28 shown in Fig.. 1. The duct, 38', is controlled by valve mechanism and coperating gage tubing, which is identical with that shown in Fig. l.

normal level of fuel`therein through the ducts shown at 38b andl 46a. The spiral shaped gage tubing, 45D, has its inner end communicating with and attached to. the tube, 44h, which extends upwardly through the float chamber cover, as 'shown in Fig. 1. The outer end of the member, 45", is arranged to cooperate with the valve, 47. The valve, 47, coperates with the valve seat, 48, for the purpose of regulating communication between atmosphere and the fuel chamber. A compression spring, 49, is interposed between the valve, 47, and the casing, and functions to hold the valve, 47, normally against its seat, 48. In the operation of thedevice shown in this figure, a vacuum is produced at the throat ,of the small venturi, 34", which is communicated to the fuel chamber. When a certain predeterizs mined vacuum has been produced in the chamber, the gage tubing, 45h, is permitted to expand and forcevthe valve, 4T, away from its seat, and thereby provide communication between atmosphere and the fuel chamber. When the vacuum in this chamber again falls below a predetermined amount, the gage tubing, 45, contracts to its original shape and permits the valve to seat, so that the required suction in the fuel chamber may be again obtained.

In Fig. 4, I have shown a modified arrangement Which is similar to that shown in Fig. 3, except that the small venturi, 34, is located at a point posterior to the throttle. The gage tubing, 45, in this figure is arranged to coperate with a valve, similar in all respects to that shown in Fig. 3 for the purpose of admitting air to thefuel chamber when a certain predetermined suction has been produced therein.

In all of the constructions thus far described, the interior of the gage tubing is subjected to atmospheric pressure, and the exterior thereof subjected to a reduced pressure. It is of course apparent that this arrangement may be reversed, 'and the interior subjected to the reduced pressure or suction, and the exterior to atmospheric pressure, or some pressure which is greater than that which is maintained in the fuel chamber.

In Fi 5 I have shown such an arrangement. n the construction here illustrated, the tube, 44d, extends through the float chamber cover, and is attached to the gage tub- 1ng, 45d, disposed outside of the float chamber. The tube, 44", affords communication between the interior of the float chamber and the interior of the gage tubing, 45d,

whereby the interior of the gage tubing is4 subjected to the same suction as is the chamber. The free end of the gage tubing,

45d, coperates with a valve, 47d, which is similar in all respects to that shown in Fig. 3, for the purpose of affording communication between atmosphere and the ioat chamber. If desired, the free end of the gage tubing, 45d, may be arranged to coperate with a valve for controlling communication between the float chamber and the source of suction, as is shown in Figs. 1 and 2.

Having thus described my invention, what I claim is:

1. In a vacuum feed carbureter the combination of a fuel chamber, means for producing a partial vacuum in said chamber for the purpose of lifting fuel thereto, valve mechanism for regulating the vacuum in said chamber and curved gage tubing responsive to the vacuum produced 1n said chamber for operating said valve.

2. In a vacuum feed carbureter the combination of a fuel chamber, means for producing a partial vacuum in said chamber for the purpose of lifting fuel thereto, valve mechanism for regulating the vacuum pre-- duced in said. chamber, and curved gage tubing for operating said valve mechanism, said tubing having its interior and exterior subjected to different pressures, the differential varying with the degree of vacuum produced in the fuel chamber.

3. In a carbureter the combination of a. fuel chamber and curved gage 'tubing for regulating the vacuum in said chamber, Said tubing having its interior and exterior subjected to different pressures, the differential varying with the degree of vacuum produced in the chamber.

4. In a carbureter the combination of a. fuel chamber, means for producing a partial vacuum in the chamber, said chamber having a duct affording communication between the chamber and atmosphere, and curved gage tubing responsive to the vacuum produced'in said chamber for regulating the passage of air through said duct.

5. In a carbureter the combination of a. fuel chamber, means for producing a partial vacuum in said chamber, curved gage tubing in said chamber and disposed above the normal level of fuel therein, one end of said tubing being fixed and having its interior communicating with atmosphere, and valve mechanism controlled by the free end of said tubing for regulating the vacuum in said chamber.

6. In a carbureter the combination of a fuel chamber, means for producing a partial vacuum in said chamber, said chamber being `provided with a duct affording communication between atmosphere and the chamber, curved gage tubing in said chamber and disposed above the normal level of fuel therein, one end of said tubing being fixed and having its interior communicating with atmosphere, and a valve for said duct, said valve being operated by the free end of the tubing for the purpose of regulating the passage of air through said duct.

In Witness whereof, I hereunto subscribe my name this 19 day of June, 1919.

CLIFFORD C. BRADBURY. Witnesses:

MARY A. COOK, ANDREW WINTERCORN. 

